1. Of or pertaining to a synod; transacted in, or authorised by, a synod; as, synodical proceedings or forms. A synodical epistle.
2. (Science: astronomy) Pertaining to conjunction, especially to the period between two successive conjunctions; extending from one conjunction, as of the moon or a planet with the sun, to the next; as, a synodical month (see lunar month, under Month); the synodical revolution of the moon or a planet.
Origin: L. Synodicus, Gr., cf. F. Synodique.